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  • A4 Uses "Lean and Mean" 3GS Cortex A8 Chip?


    Relying on unnamed sources, Jon Stokes at Ars Technica is asserting that the Apple's new A4 system-on-a-chip is based on a stripped-down Cortex A8 CPU, and not the faster A9 that some have been speculating about. The iPhone 3GS and iPod touch are based on the A8, though underclocked to 600 MHz to save power. The CPU on the A4 SoC is believed to run at 1 GHz clock speed.

    When the A4 was announced along with the iPad in January, many observers theorized that the CPU would be a wholly new design that Apple would have developed in-house with the talent from their acquisition of chipmaker P.A. Semi. After the device's specs were revealed, however, it seemed more likely that the CPU was a dual core Cortex-A9 with advanced power-management technology to achieve the 10-hour battery life that Apple claimed.

    According to Stokes's sources, though, Apple was able to run the A8 chip up to 1 GHz and still save power because I/O demands were limited. "With one 30-pin connector on the bottom and no integrated camera of any kind," Stokes writes, "the A4 needs a lot less in the way of I/O support than comparable chips... It's lean and mean to a degree that isn't possible with an off-the-shelf SoC." If this supposition proves correct, it could explain why Apple decided to ship the iPad - at least in its initial version - without a camera. lack of a camera has frequently been mentioned as a disappointment by many observers. The lack of camera support in the hardware allowed Apple to improve performance, Stokes theorizes, suggesting that "Apple has probably ditched some dedicated image processing blocks."

    P.A. Semi's role in the development of the A4 chip may have been limited to power management, Stokes thinks. Noting that the new hires had a little time between when P.A. Semi was acquired in April 2008 and the release of the iPad in January 2010, Stokes suggests they brought their "power-gating" expertise from the development of the PWRficient chipset, which was based on two 2GHz superscalar PowerPC cores running at 2 GHz and had a draw of as little as 5 watts. Power gating requires shutting down the parts of a chip that aren't in use, which is difficult to do on high-speed chips. Killing most of the I/O and image processing blocks would have allowed Apple to squeeze a lot more speed out of the A8.

    A separate story on VentureBeat early last month also asserted that the P.A. Semi team didn't work on the A4, but rather the VLSI team that had been developing Apple's custom silicon going back to the northbridges on the G4 and G5. Ars's Stokes joins other observers in speculating that the A4 may power a future iPhone release.
    This article was originally published in forum thread: A4 Uses "Lean and Mean" 3GS Cortex A8 Chip? started by Paul Daniel Ash View original post
    Comments 28 Comments
    1. steve-z17's Avatar
      steve-z17 -
      By the time the 2nd gen of the iPad comes out you'll still be able to sell your 1st gen for quite a bit of money, that's at least a down payment! No need to wait when you can be the awesome friend who has an iPad from the start
    1. NessLookAlike's Avatar
      NessLookAlike -
      Quote Originally Posted by politicalslug View Post
      That's disappointing. I'd rather half the battery life with a Tegra 2 or comparable A9 based SoC. And I may not upgrade my iPhone 3GS in the summer if it's using this A8 chip. That would be a waste of an upgrade.
      I know, right?

      For all the front-facing-camera haters: if the technology is there, someone will "make an app for that". Maybe the front facing camera would have lead to an upstart of video call/front facing apps? Video calling [phone] devices do exist, and I think it would be pretty awesome sometimes to video chat with a few friends through their laptops, skype, or somesuch. Since the intended goal could just be limited to capturing the user's face, it wouldn't have to be too great of a camera either.

      Also, think of another great use of the camera in terms of security: you forget where exactly you put the iPad, or someone took it and is now using it, you can have instant access to see contextual location and/or identity of the thief, and this could be uploaded to some Apple pay-for-use service like the one that tracks GPS location. Also, facial recognition software could be pretty neat.

      In the least, Apple should tack on a regular camera to the back or somewhere convenient so that we can use the virtual reality overlay to see information about our current location placed over the capture image. I thought Apple's big deal was to be innovative? These things would have been innovative.
    1. awesomeSlayer's Avatar
      awesomeSlayer -
      Quote Originally Posted by StealthBravo View Post
      sure, who needs wifi either.
      People who like consume OVER 9000 MB of data.
    1. StealthBravo's Avatar
      StealthBravo -
      It was sarcasm
    1. Teoyaomqui's Avatar
      Teoyaomqui -
      Quote Originally Posted by mikerlx View Post
      Why do you guys keep talking about front facing cameras???? We (collectively) have never had a cellphone with a front facing camera to ever do video conference OR ichat anywhere near a cellphone. That tech has not existed on a cellphone also there is no service provider offering this on a cellphone...Am I wrong on this info??
      [ame=http://www.youtube.com/watch?v=VP19WoVBeU4]YouTube - Sony Ericsson K800 video call[/ame]
    1. pyromcr's Avatar
      pyromcr -
      the a4 chip, the only somewhat cool thing about the ipad...
    1. secks's Avatar
      secks -
      iPad 1G doesn't have a camera .. iPad 2G will ..
      this is the way apple does biz .. hold out features so ppl have to upgrade ..
      you can't give them everything at once .. :/
      greedy biz
    1. StealthBravo's Avatar
      StealthBravo -
      ^ smart biz